How to Check the Second Generation DSM ECU for an EPROM
These instructions only apply to cars with Mitsubishi-equipped engines.
does not assume any responsibility for the use of this document or its
Here is a handy table which you can print out to record your ECU
information. As long as you have your ECU open, you might as well record this
information so you will have it available if you order an ECU upgrade.
|1.8l / 2.0l / turbo
|CA or similar / Federal
|Auto / Manual
|YES / NO
|ECU part number
|YES / NO
|Microcontroller Code #
|YES / NO
|YES / NO
- Locate the ECU. Figure 1 shows
the ECU in the center console, underneath the radio. Note that this figure has
a slight error - the ECU actually stands vertically. Figure 2
shows this fact (your view might be slightly different depending upon stereo
equipment options installed). To get to the Figure 2 view,
you will have to remove the center console carpeted kick panels from both the
driver and passenger sides.
- Remove the ECU. There are four plug connectors
(encircled in green in Figure 2) which must be removed. There
are three bolts that hold the ECU in place. One is circled in yellow. There is
also a bolt that you can't quite see since it appears sideways in this photo.
The area it occupies is located inside the yellow rectangle. There is yet
another bolt on the passenger side mounted similarly. When removing the ECU,
you might have to wiggle it around a bit - there are other wire harnesses in the
area, making for a tight squeeze.
- Open up the ECU. There are four screws on the
outside of the case.
Be absolutely certain that you are using the correct size
Phillips screwdriver. For some reason, they put tons of torque on second
generation ECU screws. The wrong size head will lead to stripping the screw
- Check for external EPROM. The EPROM in Figure 3
has a red circle on it. If your ECU looks similar to Figure 3,
but is missing this EPROM, any ECU upgrade will involve the use of a
daughterboard which plugs into where the microcontroller chip is.
- Gather part numbers. The EPROM in Figure
3 has an EPROM number of EB23C (circled in red). The microcontroller
number is circled in green. We are interested in the number of the form EXXX.
On this particular ECU, the number is E100. Ignore the numbers "MH6311"
and "76C55T" - these are internal Mitsubishi part numbers only. At
the top of Figure 3, there is a board revision number (circled
in blue). This ECU has a rev number of JE331B677C. Your number should be close
to this one, perhaps varying in the last letter. There is also an ECU part
number stamped on the ECU harness connector (circled in purple). This ECU has
part number 1672B.
- Check the ConfigID. There are two
configuration-identification resistors. The existence or absence of these
resistors let the ECU know things about the engine it will be controlling. In
this way, Mitsubishi can build one ECU, solder one of four different resistor
combinations in, and re-use that ECU for four different engine packages. These
resistors are R255 and R256 (circled in yellow in Figure 3).
Please note whether or not there are resistors soldered in at those two
- You are done! Reverse the above steps to
re-install your ECU.